Regression from 4.1.5 to 4.2.3: "Type instantiation is excessively deep and possibly infinite."

Bug Report

The attached playground compiles happily and quickly in Typescript 4.1.5, but fails with "Type instantiation is excessively deep and possibly infinite" in Typescript 4.2.3. Is a conditional distributing that didn't use to?

🔎 Search Terms

🕗 Version & Regression Information

• This changed between versions 4.1.5 and 4.2.3
• Fails on nightly as well

⏯ Playground Link

Playground link with relevant code

💻 Code

🙁 Actual behavior

4.2.3: Compilation error
nightly: Compilation error

🙂 Expected behavior

4.1.5: Compiles quickly and works fine

リンクされた TypeScript Playground の再現例から始め、4.1.5、4.2.3、nightly でのコンパイルを比較します。例を縮小して、変更された conditional type または instantiation の挙動を特定します。縮小したケースを使ってコンパイラーでの調査を進め、回帰テストを追加します。再現例が excessively deep instantiation error なしで正常にコンパイルできれば完了です。